This invention relates to a method for curing hydroxy-terminated prepolymers and to a curing agent for use therewith. More particularly, this invention concerns itself with a method for curing poly(glycidyl 2,2-dinitro-2-fluoroethoxide) by utilizing tris (.beta.-isocyanoethyl) nitromethane as the curing agent.
With the increased employment of propellants and propellant systems, a considerable research effort has been conducted in an attempt to develop new propellant materials. One such material is poly(glycidyl 2,2-dinitro-2-fluoroethoxide.) This is a thermally stable, hydroxy-terminated propolymer that can be mixed with conventional propellant ingredients and then cast cured as an explosive or propellant composition.
The conventional method for curing hydroxy-terminated prepolymers of the type contemplated by this invention utilizes a triol such as trimethylol propane or 1,2,6-hexanetriol as the cross-linking agent and a diisocyanate such as toluene diisocyanate or hexamethylene diisocyanate as the curing agent. However, the use of the conventional method referred to above, as a means for curing the poly(glycidyl 2,2-dinitro-2-2fluoroethoxide) prepolymer has proven to be unsuccessful. On the other hand, it has been found that the use of tris (.beta.-isocyanoethyl) nitromethane provides a novel means for effecting the cure of hydroxy-terminated prepolymers. For example, poly(glycidyl 2,2 dinitro-2-fluroethoxide) has been developed as an important constituent of high density impulse solid propellants. However, its utilization has been severely limited because of the difficulties encountered in attempts at effecting its cure. Prior art methods, such as that referred to above, have either been unsuccessful or highly inefficient. The use of tris (.beta.-isocyanoethyl) nitromethane as a curing agent, however, overcomes these disadvantages.
Accordingly, the primary object of this invention is to provide a novel curing agent for curing hydroxy-terminated prepolymers.
Still another object of this invention is to provide a simple and efficient method for effecting the cure of poly (glycidyl 2,2-dinitro-2-fluoroethoxide.)
The above and still other objects and advantages of the present invention will become more readily apparent upon consideration of the following detailed description thereof.